MESA, Ariz. — When the A’s traded for Mike Fiers in August of last season, they were in the midst of a playoff push but needed another arm. The bullpen remained the club’s signature weapon, but the A’s knew they couldn’t survive on that alone. To say it was the perfect match at the perfect time might be an understatement.

Shortly after Fiers joined the A’s, the club’s best pitcher, Sean Manaea, had to have shoulder surgery. Fiers stepped into the role as the No. 1 starter. In his first seven starts with the A’s, they won seven games. Fiers compiled a 3.74 ERA in 53 innings, leading the team to its first playoff berth since 2014.

In short, Fiers came as good as advertised.

“That’s what you hope for when you bring a guy in,” manager Bob Melvin said Saturday. “You try not to put too much pressure on him. It seemed like when he went out there, we won. For the team in the position we were, that...